diff --git a/app/models/ticket/number/date.rb b/app/models/ticket/number/date.rb
index 323abd7d7..8e57f5b65 100644
--- a/app/models/ticket/number/date.rb
+++ b/app/models/ticket/number/date.rb
@@ -65,6 +65,7 @@ module Ticket::Number::Date
   end
 
   def check(string)
+    return if !string || string.empty?
 
     # get config
     system_id           = Setting.get('system_id') || ''
diff --git a/app/models/ticket/number/increment.rb b/app/models/ticket/number/increment.rb
index 973348ca7..d268b44d9 100644
--- a/app/models/ticket/number/increment.rb
+++ b/app/models/ticket/number/increment.rb
@@ -70,6 +70,7 @@ module Ticket::Number::Increment
   end
 
   def check(string)
+    return if !string || string.empty?
 
     # get config
     system_id           = Setting.get('system_id') || ''